Treatment of sewage, industrial waste, and the like



June v22, 1937. P, a STRE'ANDER 2,084,659

TREATMENT 0F SEWAGE, INDUSTRIAL WASTE, AND THE LIKE ATTORNEY.

BYl Z June 22, 1937. P. B. sTREANDER 2,084,659

TREATMENT OF SEWAGE, INDUSTRAL WASTE, AND THE LIKE Filed April 12, 1935 4 Sheets-Sheet 2 INVENTOR,

'BY 4M/qw A TTORNEY.

June 22, 1937. P. a. STREANDER 2,084,559

TREATMENT 0F SEWAGE, INDUSTR-17ML WSTE, AND THE LIKE med April 12, 19:55 f 4 sheets-sheet s 7 INVENTOR.

' B7 l M Q ATTORNEY.

June 22, 1937. P. B. s'rREANDER 2,084,659

TREATMENT 0F SEWAGE, INDUSTRIAL WASTE, AND THE LIKE I Filed pril 12, 1935 4 Sheets-Sheet 4 i f 4. I I l l I l s i*275 I i 'l +55, a i ,l 756/ ill |177 E; 526 Il i fsa L n l 45.6 'n 325- g i g :L y I r 'V I r '1% 305 l I lf'- ,'75 I 1 J mi 3 i '326 g l L Vi 325 Y' L/b :sa f

l l 3 6'/ 206, 6 2 5 2 5 60 y 61 PHIL 1P B. STREA .ND/5R INVENTOR.

BY CEM; (274mm A ATTORNEY.

Patented June 22, 1937 UNITED STATES PATENT OFFICE TREATMENT OF SEWAGE, INDUSTRIAL WASTE, AND.' THE LIKE poration of New York Application April 12, 1935, Serial No. 16,066

8 Claims.

This invention relates to the treatment of sewage and the like and more particularly to methods of and apparatus for sewage treatment involving the preliminary removal of suspended solids, as by settling, andsubsequent filtration.

Important objects of the invention relate to. the provision of novel and advantageous methods and means for sewage treatment of the general character specified. An important feature relates to the provision, in association with a settling tank or basin, of a filter receiving the supernatant liquid substantially directly from the settling tank. Another feature relates tothe provision, in connection with a settling tank and a lter receiving liquid therefrom, of advantageous means for cleaning the filter, A further feature relates to novel and advantageous means for cleaning a filter by means of back wash or reverse flow.

In carrying out the invention in a preferred l manner, the supernatant liquid overliows from the settling tank into a channel or launder from which it flows through openings, controlled by gates or other suitable means, into a relatively deep channel provided at its bottom with one or more outlets discharging into a waste water conduit. Such outlets are normally 4closed and the supernatant liquid passes over a low wall into a filter channel preferably divided into filter sections, each comprising a section or compartment divided by a filter bed into an upper compartment and a lower filtered eilluent compartment. Due to the hydrostatic head of the liquid in the a filter channel, the liquid is forced through the lter'bed `or beds and upwardly from said lower compartments or chambers into an efiluent channel provided with an outlet somewhat below the normal level in the filter channel, provision being made of adjustable means whereby the liquid can not ordinarily flow back to the filter but can be permitted to do so when the liquid in the filter channel vis drawn down to a lower level. The vfilter bed may be of any suitable material,

, such as silica sand, crushed coal, quartz, ground glass, etc., supported on porous filter plates.

When the solids retained in a filter bed accumulate to a suflicient extent and there'is a predetermined loss of rate of filtration, the supply from the settling tank is shut ofi from. a filter section and the connections with the waste water conduit are opened to drain the filter channel down to waste wash water troughs slightly above the filter 'bed and discharging through said low wall into the waste water conduit. Preferably such wash water troughs extend substantially across the filterv channel and tend to produce a more uniform upward flow of wash water through the whole area of the filter bed and to prevent accumulation of the waste solids at a side wall of the filter channel. The means for controlling the height of liquid in the filtered eflluent chan- 'nel is then shifted to allow the water to reverse its flow and pass up through the filter bed thereby fioating the accumulated solids from the filter bed and discharging them into the waste water troughs. is completed, the apparatus is again operated ln its normal manner.

An advantageous feature of the invention is that no auxiliary units are required for washing the filter beds, such washing being done entirely by the hydrostatic head provided above the upper level of the wash water troughs. Other features, objects and advantages will appear upon consideration of the following description and of the drawings in which Fig. 1 is a horizontal section of an apparatus embodying an approved form of the invention, the section being taken along the line I-I of Fig. 2;

2 2 of Fig. 1;

Fig; 3 is a sectional view taken along the lines 3ra-3a, :Ih-3b, 3c-3c, .3d-3d, and 3e-3e of Fig. 1;

Fig. 4 is a fragmentarysectionalyiew on a larger scale of part of the structure shown in Fig. 2;

Fig. 5 is a fragmentary top plan view of the part of the structure illustrated in Fig. 4;

Fig. 6 is a fragmentary perspective view illustrating the support for the filter medium;

Fig. 7 is a section taken on line l-l of Fig. 6;

Fig. 8 is atop plan view of a second embodi- Fig. 2 is a Vertical section taken on the line ment of the invention, the View being partly in section along the line 8 8 'of Fig. 9;

Fig. 9 is a fragmentary Vertical section of the apparatusshown in Fig. 8; and r Fig. 10 is a horizontal section of apparatus embodying a third form of the invention.

Referring to- Figs. 1 to '7, the sewage or other liquid to be treated passes through a pipe or conduit l0 into a contact'tank II and around partitions or baiiles I2, extending alternately from` opposite ends of the tank, to an overflow wall I3 which is at the opposite side of the tank from the supply conduit Ill. As illustrated the overfiow Wall I3 is at the inner side of a launder I4 pro- 'jecting inwardly from a. side wall I5 of the tank When the washing of the filter bedA II, and the overow or supernatant liquid passes through one or more openings or passages I6 into one or more channels or channel sections |'I which in turn discharge over one or more walls I8 into the upper compartments I9 of lter channels or troughs 20. Preferably each iilter influent opening or passage I6 is provided with a gate 2| controlled by a handle 2|. The liquid in the upper compartments I9 passes downwardly through a iilter bed 22 of suitable material such as silica sand, crushed coal, quartz, ground glass, f

etc., into a'lower or filter effluent chamber 23|. Preferably the filter medium comprising bed 22 is sup-ported on porous tiles 24 mounted on beams or cross members 25. From the lower or eiliuent chamber 23 the filtered etlluent passes through one or more openings 26 into a chamber orl compartment 2l beneath the bottom of-a final effluent channel 28 which communicates near its top with an outlet or' discharge pipe 29. As most clearly shown in Fig. 1, the different channels or sections |'I and the filter channels or troughs I9 may be separated by walls 30 which also extend downwardly to the oors of the lower filter chambers 23 and serve to separate chambers 2'I.

l It should be understood that, while it is desirable .to divide the Various channels and compartments by the walls 30, such walls may be omitted. From the chambers 21 the ltered eluent passes up-,

wardly through openings or passages 3| into the final eliluent channel or chamber 28.

In order that some of the iilter sections may be kept in operation while others are being v cleaned it is desirable to discharge the eliluent,

the rod 35 passes.

from filter sections in use, into the upper part of the channel 28, and for a reversal of flow through a filter bed to be cleaned, it is desirable to be able to draw out the liquid from a lower part of the channel 28. This result can be obtained in different ways but, as illustrated, it is obtained by means of control devices in the form of telescopic conduits 32, each having a larger lower section 33 receiving liquid from an opening 3| and a smaller upper section 32 receiving liquid from the lower section and discharging it into the upper part of the channel 28 when the telescopic device is expanded. It will be seen that such control devices 32 serve as gates over which the liquid ilows. When a telescopic .device is contracted, liquid in the channel 23 can readily be passed in reverse ow through the corresponding lter bed section if at that time the liquid level in the corresponding upper chamber I9 of a filter channel or trough 20 be sufliciently lowered. 'I'he length of each telescopic device 32l may be varied by means of a vertical rod 35 connected with the upper end of the part 3-2 and having a screw thread connection with a hand wheel 36 supported by a bracket 31 through which Obviously the control devices 32 must be of sufficient capacity to enable a suitable rateof reverse iiow. Furthermore it will be evident that each contro-l device 32 could be replaced by an outlet in the side of the eflluent channel and a vertically slidable gate which would always keep the lower part of the opening closed.

'Ilie diierent filter inuerit channels I1 may be drained through passages 38 at the bottom thereof into a waste water conduit or chamber 39 from which the waste water may be discharged through a pipe 40 thereby enabling the by-passing of the filter when desired or a back- `wash cleaning of the iilter bed 22 when the controlling devices in the form of telescopic conduits 32 are contracted or collapsed. Normally during .vice, the gates 4| being closed at this time.

the operation of the filter the passages 38 are closedby gates 4| whose positions may be determined by means including rods 42 having screw thread connections with such gates and being rotatable in brackets 43 at the top of the apparatus. The rods 42 may be rotated by hand wheels 44. To carry off the waste wash water produced'in the back wash cleaning of the lilter bed, provision may be made of waste wash water troughs 45 in the compartments 29 and draining into the lower part of the channels through passages I6 extending through the wall or walls I8. Preferably the bottoms of the troughs 45 are inclined toward the openings 46 and the inclination of said bottoms may be adjustable by suitable supporting devices 41 for the ends of the troughs remote from the wall I8.

The operation of this form of the apparatus may be substantially as follows: The sewage supplied through the inuent pipe Il) is purified to a substantial extent by the removal of a substantial, amount of suspended solids during the passage of the sewage through the contact settling tank II, and the supernatant liquid thus clarified ilows over the wall I3 into the launder I4 and then through theY passages I6 into the channel or channels I'l and the upper compartment or compartments I9 of the filtration de- The sewage from the upper compartments I9 flows downwardly through the filter bed or beds 22, which serves to retain solids present in the sewage, into the lower filter compartments 23 and then through the compartments 21 and control devices or gates 32 into the main eluent conduit or channel 28 connected with the discharge pipe 29.

As the lter beds 22 become more and more clogged, the liquid level in the upper compartments I9 rises and when the clogging becomes too great the filter beds are cleaned one or more at a time. In cleaning a lter bed, the corresponding influent gate 2| is closed and the waste water gate 4| is opened thus draining the liquid in the upper compartment I9 down to the level of the upper edges of the waste water troughs 45. The control' device or gate 32 is then -lowered to reverse the flow of water through the filter bed 22 and by means of rapid upward ow through the iilter to float the accumulated solids from the filter bed and discharge them into the waste wash water troughs 45 from which they drain through the passages 46 and 38 into the channel 3S communicating withl the discharge pipe 40'. Upon completion of the washing, the control device 32 is restored to its normal position, the gate 4| is closed andthe influent gate 2| is opened.

In Figs. 8. and 9 there is disclosed a second embodiment in which the settling tank or basin ||a is round and the sewage from a supply pipe Illa passes upwardly through a hollow central pier 48 and is discharged therefrom into the tank through openings 49 in the pier, agitation of the liquid being minimized by means` of a baille 59 surrounding the pier at that height. The sewage flows outwardly towards the periphery of the tank and the s olids gradually settle to the bottom of the tank and are then moved to the central part of thetank and discharged into anan- -nular sump 5| by means of suitable scraping means 52 carried by a bridge 53 rotatably mount-v ed onsaid pier 48 and mounted on the inner wall |3a of a launder |4aby means of wheels 54 at the lower side of the bridgev and traveling on a rail 55 resting on the top of said wall |3a. From the sump the sludge formed by the settled solids is drawn-off through a, pipe or conduit 55a. Mounted on the bridge is a motor 56 5 which drives one or more of the Wheels 54 and also the scraping device 52.

The supernatant liquid is discharged from the tank Ha over weirs formed in the wall I3a into the launder Ma from which it passes through openings or ducts IBa into channels ortroughs lla separated by walls 30a. From the channels I'la the liquid passes over low walls |8a into upper chambers I 9a of filter troughs or channels a and then downwardly through filter beds 22a l5 into lower chambers 23a. From the chambers 23a the filtered effluent fiows through passages 26a, compartments 21a and control devices 32a into the main effluent channel 28a which discharges through a pipe 29a (at the top of Fig. 8).

When backwash cleaning of the filter beds 22a is to be effected the passages I6a are closed by gates 2Ia and gates Ma at the bottom of chambers or channels Ila are opened in order to draw off the liquid in the upper filter compartment down to the level of the upper edges of the waste water troughs 45a, the liquid thus drawn of fiowing downwardly through passages 38a into a chamber 39a from which it is discharged through a conduit 29a. As soon as the level of 30 the liquid in the upper compartment of the filter channels is vlowered to the level of the waste water troughs, the control devices 32a which serve as gates are lowered so that the water in the channel 28a can be utilized to produce 35 a reverse iiow through the filter bed and carry the solids floated from the filter bed into the `waste water troughs to be drained from the apparatus. It will be evident that the operation ofY the second form of apparatus corresponds only changes in the form of apparatus from that of the first form are such as required to adapt the apparatus for use with a round tank orone in which ,the sludge is moved toward the center of 'a revolving rake or scraping device.

In Fig. 10 there is illustrated a form of apparatus in which the back wash filters of the present invention are used in connection with sedimentation apparatus comprising long tanks into which the sewage is introduced near the upper surface of the liquid in the tanks, the supernatant liquid is removed from the tanks at points remote from the place of introduction of the sewage, and the sludge is drawn rearwardly along the bottoms f @ofthe tanks and discharged therefrom, at the ficis' where the influent sewage is admitted, and

removed through a pipe 55h. Referring to said Fig. l0 the sewage -is supplied through a conduit Ille to a channel 51 and through passages 58, con- 60 trolled by gates 59, into tanks IIb and llc in which a substantial proportion of the suspended solids settle to the bottoms of the tanks in the form of sludge, which is moved to the infiuent end of the tank by scraper mechanism 52a andfde- 55 posited in sumps or hoppers 5|a, the supernatant liquid being discharged over an overfiow wallY |3b into a launder Mb extending around the sides of the structure'formed by the two tanks I Ib and I Ic at the end of said structure remote from the 70 influent conduit I0c. The launder |4b communicates with filter channels 20h through openings or passages |61), controlled by gates 2lb, and with channels Il'b separated from the filter channels by low walls lsb. From the upper compartments ISb of the filter chambers or channels 2Gb closely to that of the first form and that the the liquid passes downwardly through the filter beds and upwardly through control devices 32h into a final efliuent channel 282) from which it is discharged through a pipe 29h. In this as well as in the other forms the filter beds may be cleaned by reversing the fiow of the liquid theremore desirable to clean one or more filter sections at a time and to maintain the normal operation of the other filter sections.

It will be evident that, if the level of the liquid is. not lowered to any great extent in cleaning one or more lter sections, a better reverse flow can be maintained during the cleaning operation, and that such maintenance of liquid level can be effected to greatest advantage by using forms of apparatus in which the filter is divided into a relatively large number of sections. l

It should be understood that various changes may be made and that certain features may be used without others, without departing from the true scope and spirit of the invention.

Having thus described my invention, I claim:

l. The combination of a downward fiow filter receiving infiuent liquid to be filtered, shut-ofi` means for preventing fiow of influent liquid to the filter, an effluent channel receiving filtered effluent from the filter, shut-ofi means to prevent backward fiow from the effluent channel to the filter, and means for lowering the liquid level in the infiuent side of the filter when the infiuent liquid and the emuent channel are shut ofi from the filter whereby, upon opening of the shut-off means between the filter and the effluent channel, liquid from the efliuent channel will be caused to fiow back through the filter and clean the same.

2. The combination with a downward flow filter receiving liquid to be filtered, an effluent channel receiving the filtered effluent from said filter, and

means for effecting reverse-fiow cleaning of said filter by filtered effluent including means for lowering the liquid level in the infiuent part of the filter below the level in the effluent channel, and waste-wash-water drainage means in said filter, said drainage means including troughs at the influent side of the filter communicating with the exterior of the filter.

3. In apparatus of the class described,.an infiuent channel, a filter channel separated therefrom by a relatively low wall over which the liquid .from said influent chamber fiows, a filter bed dividing the filter channel into upper and lowerv compartments, an efiluent channel receiving the filtered effluent and having an outlet at a substantial height above the filter bed, said low wall having an opening above the level of said filter bed, a trough above said filter bed discharging through said'opening in the low wall, and means at the bottom of said influent channel to drain the same and lower the liquid to the level of said trough, whereby the liquid in the effluent charnber may flow in a reverse direction through said filter bed to remove the impurities from said bed and discharge them from the filter through said trough.

4. In apparatus of the class described, an influent channel receiving influent liquid to be filtered, means vfor shutting oi the supply of influent liquid, normally closed means for discharging liquid from said influent channel, a lter channelseparated from the influent channel by a relatively low wall having an opening therethrough, a iilter bed below said .opening dividing the lter channel intoan upper chamber and a lower chamber, a drainage trough above the lter bed and discharging through said opening, an effluent. channel receiving liquid from said lower chamber and having an outlet at a substantial distance above said bed, and means normally preventing back ow from the ellluent channel to the lower filter compartment but shiftable to permit said back flow to be used, after draining the filter bed to the level of said trough,'in washing the ilter bed and discharging the waste wash water through said trough.

5. In apparatus of the class described, an influent channel divided into sections, a iilter channel divided into corresponding sections separated from the influent channel sections by relatively low walls each having an opening therethrough, a trough in each of the filter sections communicating with the corresponding opening, a filter bed in each filter section below the level of the corresponding trough and dividing the lterwsections into upper and lower compartments, an eluent channel having a connection with each of said lower compartments and having an outlet at a level higher than that of the troughs,

means for' closing the various connections between the lower lter .compartments and the eiiluent channel, means for draining the various influent channel sections, and means for shut'- ting off the supply of liquid to the various inuent channel sections.

6. The combination of an overflow wall, a channel receiving influent liquid from said overflow wall, a lter bed in said channel dividing it into an upper chamber receiving the overflow liquid and a lower filtered ellluent chamber, an effluent discharge channel receiving said filtered eliiuent andhaving an outlet above the level of the lter bed, adjustable overflow means between able liquid in the ltered ellluent channel toflow upwardly through the filter and outwardly through said discharge means at-the lower part of the upper compartment when said discharge means is open.

and means for reverseiiow cleaning of the filtery bed including means for shutting olf the supply of liquid to the influent channel, means for draining the influent channel to lower the level of the liquid in the influent chamber of the iilter to substantially the level of the opening in said low wall and permitting a reverse flow of liquid from the eflluent channel through said filter bed to clean the same.

8. The combination with a settling tank, to which solid-containing liquid is supplied at an influent end and discharged in clarified condition over the tank wall at the other end thereof, C

and means for movingthe settled sludge back along the tank bottom to the influent end, of a launder extending across the discharge endof the settling tank and along the sides of the tank, of influent channels outside of the por.

tions of the launder at the sides of the settling tank, each of said influent channels being divided into sections, a gate device for separating each of said'sections from the launder, filter channel sections at the outer side of said inuent channels and separated therefrom by relatively low walls each having an opening therethrough, means for separately draining said iniiuent channel sections, filter beds in said filter channel sections, below said openings and dividing the filter channel sections into upper and' lower compartments, an eilluent channel extending across the discharge end of the settling tank just outside of said launder and along the outer sides of said filter channel sections where it is connected with the lower compartment of each of said lter sections, and .gates between the adjacent portions of the launder and the eiiluent channel.

' PHILIP B. STREANDER. 

